Polycarbonate-polyester alloys are excellent in heat resistance and chemical resistance and particularly often used in automotive parts. In recent years, further thinning of the parts is demanded from a viewpoint of weight reduction, and improvement in the flowability of materials is requested. Further, higher rigidity, higher heat resistance and better flame retardancy of the materials are requested in response to the thinning of the products.
Polycarbonate-polylactic acid alloys, which belong to polycarbonate-polyester alloys not only have the above properties, but also enable to increase the flowability of polycarbonate (optionally abbreviated as PC hereinafter) due to the characteristics of high flowability that belongs to polylactic acid.
Also, when poly lactic acid is alloyed with polycarbonate and then burned, it is considered to release reduced amount of toxic gases because of its chemical structure so that environmentally friendly polycarbonate alloys can be expected.
Conventional PC-polyester alloys are superior in heat resistance and chemical resistance, but poor in flow ability, so that alloying with styrene type resins or addition of plasticizers is generally used in order to increase the flowability of PC resins (for example, refer to Patent document 1), PC-polylactic acid alloys having pearlescence, good flowability and good thermal and mechanical properties have been known, yet further improvement in flowability is required for molded articles with a complex shape like office automation equipment, and the like (for example, refer to Patent document 2). However, such alloys are poor in rigidity and low in flame retardancy, limiting applications of molded articles thereof.
Technologies to blend PC-thermoplastic polyester alloys with glass fibers have been also disclosed (for example, refer to Patent documents 3 and 4), however, they are only for aromatic polyesters, and none of those for fatty acid polyesters is described. Such technologies are good in improving rigidity, but insufficient in flowability and may reduce heat resistance.
While technologies to add inorganic fillers with an aspect ratio of 5 or more to fatty acid polyesters have been disclosed (for example, refer to Patent document 5), rigidity, heat resistance, flame retardancy and impact resistance are low, limiting applications of molded articles.
Further, a polycarbonate resin has self-extinguishing properties, however, in the field of electric and electronic equipment such as office automation equipment, information and communication equipment, home appliances and the like, there is a field in which a higher level of flame retardancy is demanded and the addition of various flame retardants is tried for its improvement.
Halogen type flame retardants such as halogenated bisphenol. A, halogenated polycarbonate oligomers and the like are used as a method to improve the flame retardancy of a polycarbonate resin in a combination with auxiliary flame retardants such as antimony oxide and the like in terms of flame retardant efficiency.
However, in recent years, the market demands a flame resisting method with halogen-free flame retardants from a viewpoint of safety and an effect on the environment in disposal and incineration.
Various methods are proposed, in which organophosphorus type flame retardants, particularly organophosphate ester compounds as halogen-free flame retardants show excellent flame retardancy and also serve as a plasticizer when blended to form a polycarbonate resin composition.
On the other hand, a technology to add both glass fibers and phosphorous type flame retardants to a resin comprising polylactic acid as a major component is also disclosed (for example, refer to Patent document 6), but it is required to add a large volume of such phosphate type flame retardants in order to impart flame retardancy, resulting in insufficient heat resistance, impact strength and water resistance. There is no disclosure on blending of PC with polylactic acid and on the effectiveness of phosphate type tire retardants to increase heat resistance and stability of the PC-polylactic acid alloys.    Patent document 1: Japanese Patent Application Publication No. H7 (1995)-68445    Patent document 2: Japanese Patent Application Laid-Open No. H7 (1995)-109413    Patent document 3: Japanese Patent Application Laid-Open No. S54 (1979)-94556    Patent document 4: Japanese Patent Application Laid-Open No. H6 (1994)-49344    Patent document 5: Japanese Patent Application Laid-Open No. 2002-105298    Patent document 6: Japanese Patent Application Laid-Open No. 2004-175831